<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
</head>
<body>

</body>
</html>


<script>
	var num;
	function show() {
		num =10;
		alert(num);
	}

	show();
	alert(num);
</script>